Papers by Keyword: Biomimetics

Abstract: The article discusses the advances of biomimetics in imitation of the laws of nature. Everything in nature is perfect. Nature is smart, rational and innovative, that’s why scientists and engineers from all over the world are trying to reproduce natural principles in the laboratory. The use of ideas borrowed from wildlife is called biomimetics. Since Leonardo da Vinci tried to design an airplane that simulates the flight of birds, the biomimetics - the science of using natural attributes, functions, and structures in technical equipment was first spoken about. Many scientists look to nature in the hope of finding solutions to the complex issues that humans face. In this regard, the nature provides many ready-made solutions - we just need to adapt them to specific technical problems.

Abstract: The article discusses the features of biomimetics as a science that allows to suggest technologies for creating new technologies. Strange to relate, the man is a being completely unadapted to life. At the same time, man made a lot of discoveries precisely thanks to the observation of animals — from primitive tools based on the teeth of other animals to the first flying machines. Over time, the human civilization has defined a whole direction in science, which explores mechanisms in nature in order to use them for the benefit of man. With the help of biomimetics (from the Latin "bios" - life and "mimesis" - imitation), many problems from medicine, architecture, transport and energy were solved.

Abstract: The great potentials of wood species have not yet been fully tapped in Ecuador in order to propose feasible and eco-friendly alternatives that allow reducing/replacing conventional building materials. This investigation aims to determine the physical-mechanical properties of lightweight bidirectional sandwich-like composite wall panels made of bamboo (Dendrocalamus asper), melina (Gmelina arborea) and balsa (Ochroma pyramidale). To fulfil this purpose, 80 samples from four prototype biopanels were tested in accordance to the current American Society for Testing and Materials (ASTM) standards. The experimental results were validated and compensated by performing a total of 79 finite element analyses (FEA) that in turn allowed evaluating and analyzing both the mechanical efficiency and the biomechanical performance of the proposed biopanels. The results in this investigation showed sandwich-like composite wall biopanels with an enhanced mechanical efficiency that is up to nine times higher than steel, concrete, aluminum, wood and bricks. Results from the biomechanical analyses confirm the practical utilization of the proposed biopanels in low-rise and mid-rise buildings (i.e. between two and ten stories) located in high-risk seismic and windy regions. Thus, its implementation in the actual construction system will definitely implicate important upgrades in terms of structural optimization and sustainable practices. Indeed, the proposed wall biopanels are meant to be used in the rebuilding process of the dramatically affected areas during the 2016 Ecuador earthquake.

Abstract: This study develops a new, facile and rapid process bioinspired on rice leaf with the aim of producing a hybrid composite coating in a first attempt to obtain a superhydrophobic coating with enhanced erosion resistance properties. Rice leaves (Oryza sativa L.) are made of hierarchical structures consisting of micropapillae and waxy nanobumps which confer to the surface a contact angle of 164° as Lotus leaf does. In particular, rice leaves accumulate amorphous silica inside and on the surface with various morphologies. This kind of silica is produced by absorbing silicates from the soil under specific conditions of temperature and pressure. The presence of biosilica in rice leaves is useful for preventing diseases or improves mechanical properties of the leaves. Single-step and two-step processes are the two strategies applied for generating a superhydrophobic coating by electrochemical deposition of ZnCl₂, α-Al₂O₃ and lauric acid (C₁₁H₂₃COOH) onto commercial pure aluminum substrate. The static contact angle measured on the coating gives values of 170° and 1° for the sliding angle conducing to a coating with superhydrophobic and self-cleaning properties. Various characterization techniques are used to determine chemical and morphological structure such as FESEM, XPS or FTIR. On one hand, in morphological analysis, flower-like structure is obtained with petals thickness of 70nm corresponding to the nanostructured contribution to the system. On the other hand, chemical analysis concludes the generation of zinc laurate (Zn (C₁₁H₂₃COO)₂) as a major compound contributing to the reduction of surface tension and increasing the superhydrophobic character of the coating as well.

Abstract: Peptide – mediated biomineralization is an emerging and promising biomimetic approach for the synthesis of nanomaterials. This nature – inspired technique of producing inorganic nanostructures depends on the biomineralization peptide to control the shape and morphology of the prevailing inorganic nanostructure. One of the challenges in peptide – mediated biomineralization is controlling the 3D arrangement and orientation of the peptide. Recently, we have developed a peptide platform that can specify and direct the geometric arrangement and spatial orientation of the biomineralization peptide. The peptide platform is composed of two segments: a metal binding sequence, and the tetramerization domain of the tumor suppressor p53 protein, which acts as the oligomerization control element. The resulting fusion peptide exhibits a spatially – fixed and well – controlled assembly of the palladium binding sequence. This present study demonstrates the utility and efficacy of this peptide platform to bimetallic materials. Monodispersed 5 nm bimetallic PdAg nanoparticles were synthesized using the oligomerization – controlled biomineralization peptide. The synthesis was carried out in an aqueous environment, void of harsh reagents. When other fusion biomineralization peptides were used to synthesize bimetallic PdAg nanoparticles, less ordered nanoparticles were yielded. The results highlight the importance of controlled assembly on bimetallic nanoparticle formation through biomineralization. The presented method offers a straightforward manner of creating monodispersed and extremely small nanoparticles, which are useful in a wide array of applications.

Abstract: A Knee-Ankle-Foot orthosis (KAFO) is used as a supportive device by individuals with lower limb disability. A type of KAFO that allows knee flexion-extension is prescribed for people who need knee stability in the transverse and frontal planes. In such an orthosis, mimicking the human knee motion is vital to avoid relative motion (called pistoning) between the limb and the orthosis. A four-bar mechanism, owing to its polycentric nature, simplicity and ease of fabrication can provide a customizable, biomimetic solution. This paper presents an improved and robust optimization approach to synthesize a four-bar mechanism to closely mimic the anatomical knee motion. The reference human knee centrode is obtained from literature. A genetic algorithm is used for optimal synthesis of the fourbar mechanism. Results show that the average error between the reference centrode and the centrode of the synthesized four-bar mechanism is very small (0.2 mm). Thus, the synthesized crossed four-bar linkage can reproduce better anthropomorphic characteristics of the knee joint. The methodology can be used for the design of customized orthotic knee joints for KAFOs and knee braces.

Abstract: It is well known that polyvinyl alcohol hydrogel-based (PVA-H) biomaterials are promising materials for damaged articular cartilage replacement, but their application for bone tissue engineering is restricted due to insufficient mechanical properties. Thus, to meet the demands of the bone substitute material, PVA-H are reinforced with hydroxyapatite (HAp) crystals. The current research is focused on the preparation of nanosized hydroxyapatite/polyvinyl alcohol (n-HAp/PVA) composite material that mimics the microstructure and mechanical properties of natural bone tissue. The aim of this work is to determine the impact of various technological parameters of n-HAp/PVA composite in situ synthesis on the chemical purity of final product. Obtained results confirmed that the main inorganic phase of the composite material is HAp with an average crystallite size of 20.39 nm, however β-tricalcium phosphate (β-TCP) and CaO phases are also present. Obtained results showed that it is possible to decrease the amount of potentially harmful by-products, e.g. CaO in the composite material from 1.57wt% to 0.32wt% by increasing the homogenization speed of starting suspension from 400 rpm up to 7000 rpm, though the main influence on the obtained products chemical purity has 5wt% polyvinyl alcohol aqueous solution. Based on the results, it is concluded that the combination of starting suspension stirring temperature, homogenization speed and homogenization time of 23°C, 7000 rpm and 2 min, respectively, allows to obtain nanocomposite with the lowest amount of impurities (HAp: 98.08wt%; β-TCP: 1.60wt%; CaO: 0.32wt%).

Abstract: Hydroxyapatite Ca₁₀(PO₄)₆(OH)₂: (HAp) with stoichiometric composition and Ca/P (ratio) = 1.67 has attracted much attention in the context of bone transplant due to its similarity with the mineral constituent of mammals bone and teeth. It is frequently used as a filler to replace amputated bone or as a coating to promote bone ingrowth into prosthetic implants. Biomimetics or biomimicry is the imitation of the models, systems, and elements of nature for the purpose of solving complex human problems. Living organisms have evolved well-adapted structures and materials over geological time through natural selection. Biomimetics has given rise to new technologies inspired by biological solutions at macro and nanoscales. Nanostructure modification of dental implants has long been sought as a means to improve osseointegration through enhanced biomimicry of host structures. Several methods have been proposed and demonstrated for creating nanotopographic features.In the present investigation hydroxyapatite and metals (scandium, magnesium and neodymium) doped hydroxyapatite were successfully synthesized in laboratory by chemical precipitation using hydrothermal route and also by taking ethylene diamine tetra-acetic acid as a complexing reagent. The crystal, grain, and bonding structures of resulting HAp were characterized structurally using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques and spectroscopically using Fourier transform infrared (FT-IR) techniques. From SEM analysis it was found that the irregular structure of HAp changes to nanorods with EDTA HAp which further gets converted to dandelium structure with scandium doping, plate structure with magnesium doping and whiskers structure on doping with neodymium.

Abstract: In our work on micro-fabricated hair-sensors, inspired by the flow-sensitive sensors found on crickets, we have made great progress. Initially delivering mediocre performance compared to their natural counter parts they have evolved into capable sensors with thresholds roughly a factor of 30 larger than of their natural equivalents. Due to this disparity, and also instigated by our work on fly-halteres inspired rotation rate sensors and desert locust ear-drum mimicking membrane struc- tures, we have analysed the differences in performance between natural and man-made sensors. We conclude that two major drawbacks of main-stream micro-fabrication are the lack of easily applicable soft materials, as well as the limitations imposed by photolithography based fabrication with respect to freeform 3D shaping of structures. Currently we are targeting additive manufacturing for biomimetic sensor structures and in this contribution we report initial results of 3D printed sensor structures.

Abstract: Two of the key purposes of future NASA’s solar system exploration of planetary bodies are the search for potentially preserved bio-signatures and for habitable regions. To address these objectives, a biologically inspired wireline deep rotary-percussive drill, called Auto-Gopher, has been developed. This drill employs a piezoelectric actuated percussive mechanism for generating impulsive stresses and breaking formations, and an electric motor to rotate the bit to break material and remove the cuttings. Initially, the drill was designed as percussive mechanism for sampling ice and was demonstrated in 2005 at Lake Vida, Antarctica, reaching about 2 m depth. The lessons learned suggested there is a need to augment the percussive action with bit rotation in order to maximize the penetration rate. The first generation implementation of the rotary augmentation was focused on the demonstration of this capability. In 2012, during the 3-day field test, the drill reached a 3-meter deep in gypsum. A separate mechanism was used to break and remove the cores. The average drilling power consumption was in the range of 100-150 Watts, while the rate of penetration was approximately 2.4 m/hr. Currently under development is the second-generation drill, called Auto-Gopher 2. The drill will be fully autonomous. In this paper, the capabilities that are being integrated into the Auto-Gopher-2 are described and discussed.